Dunesday Runtimes Are In: ‘Dune: Part Three’ and ‘Avengers: Doomsday’ Both Go the Distance

Hollywood rarely pulls off a same-day showdown as loud as Dunesday. The nickname fuses “Dune” and “Doomsday” and covers the December 18 opening of ‘Dune: Part Three’ and ‘Avengers: Doomsday’. Robert Downey Jr. floated the name during a January chat with Timothée Chalamet.

The pairing borrows its logic from Barbenheimer, the July 2023 double bill of ‘Barbie’ and ‘Oppenheimer’. But where that duo offered contrasting tones, these are 2 large-scale sci-fi action films chasing the same premium-format screens and the same audience attention. That makes every practical detail matter more than usual, including how long each film keeps you in your seat.

Now there are numbers to work with. Current AMC Theatres listings put ‘Dune: Part Three’ at 2 hours and 30 minutes and ‘Avengers: Doomsday’ at 2 hours and 45 minutes. That is a 15-minute gap between the 2 films, and it already reshapes how a Dunesday double feature might look.

The 2 hours and 30 minutes figure is not where the film started. When advance IMAX tickets first went on sale, the listing read 2 hours and 20 minutes, or 140 minutes. AMC has since added 10 minutes, and its listing for the December 14 IMAX 70MM insider screenings shows the same 2 hours and 30 minutes.

Even with the bump, Denis Villeneuve’s finale would still be the shortest chapter of his trilogy. The first ‘Dune’ ran 155 minutes, and ‘Dune: Part Two’ reached 166 minutes according to Japan’s film rating board. An earlier IMAX press release also said 71 minutes of the then-listed 140-minute cut were filmed for IMAX, so more than half the movie was built for giant screens.

Warner Bros. has not announced an official runtime. A July rumor from journalist Jordan Ruimy, citing unnamed sources, claimed the cut ran over 3 hours, which contradicts the theater data. Until the studio weighs in, the AMC number is the best clue available.

The story itself picks up nearly 2 decades after Paul Atreides seized control of the Imperium. Now a ruthless Emperor, Paul faces the consequences of his reign as old allies return and betrayal lurks in every shadow.

“Forgive me for all I’ve done.” Experience the epic conclusion. Dune: Part Three only in theaters and IMAX December 18. #DuneMovie #FilmedforIMAX https://t.co/x9Nftg9yXd

— DUNE (@dunemovie) July 8, 2026

The Marvel side of the equation has been steadier. The Hollywood Reporter first reported a 165-minute runtime about 5 months before release. That puts the film above ‘Avengers: Infinity War’ at 149 minutes but well short of ‘Avengers: Endgame’, which runs 3 hours and 1 minute.

Directors Joe and Anthony Russo were cagey for a while, saying it was too early to name a running time while they were still deep in the edit. Anthony Russo later described the film in a Fandango sit-down as a movie of roughly 2.5 hours. Earlier rumors floated a much longer cut of around 3 hours and 30 minutes, but those were never confirmed.

Whatever the final number, the film has a lot to carry. It is the first Avengers movie since 2019, with Downey returning as Doctor Doom, Chris Hemsworth’s Thor back in a warrior mindset, and the Avengers, X-Men and Fantastic Four all joining the fight.

He used to be different. Avengers: Doomsday arrives in theaters everywhere December 18. Get your tickets now: https://t.co/J5PUbxvAkc https://t.co/OUutSMZneq

— Marvel Studios (@MarvelStudios) August 15, 2026

A tighter runtime could help theaters fit in more daily showings, which matters when 2 blockbusters are fighting over the same seats. ‘Dune: Part Three’ also has a reported advantage in premium formats. It has reportedly locked up roughly 400 North American IMAX screens for 3 weeks.

For fans planning a marathon, the math is simple. Watching both films back to back adds up to 5 hours and 15 minutes, before trailers and snack runs. That is a long day in a theater, but Dunesday is shaping up to be the kind of event people plan around.

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